JPH06220336A - Stable plastisol - Google Patents

Abstract

PURPOSE: To obtain a non-vinyl chloride based plastisol stable for a long period of storage at room temperature.

CONSTITUTION: This plastisol is a copolymer of 3 to 20 pts.wt. of unsaturated carboxylic acid compounds and 80 to 97 pts.wt. of ethylenically unsaturated compounds, wherein at least 10% of the carboxyl groups are neutralized with alkaline metal compounds and 100 pts.wt. of polymer particles having a number average particle size larger than 0.1 μm and smaller than 100 μm are dispersed in 50 to 200 pts.wt. of a plasticizer.

COPYRIGHT: (C)1994,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a non-vinyl chloride plastisol which can be stored at room temperature for a long time.

[0002]

Plastisol is a liquid or paste-like product produced by dispersing polymer particles in a liquid plasticizer and optionally adding fillers and other additives. Turns into a soft solid. That is, the polymer particles maintain their original shape without being dissolved in the plasticizer or swelling when stored at room temperature, but quickly absorb the plasticizer and gelate when heated.
Utilizing this property suitable for painting and bonding, plastisol is usefully used in the fields of transportation vehicles, ships, toys, and processed textile products.

The predominant polymer for plastisols is vinyl chloride polymer. This polymer, with the most versatile dioctyl phthalate as a plasticizer, gives stable plastisols at room temperature for months and longer. The soft plastic obtained by heating this vinyl chloride plastisol is tough. However, with increasing concern about environmental pollution, the problems of vinyl chloride polymer products have gradually come to the fore. That is, when a vinyl chloride polymer product is incinerated, hydrochloric acid and dioxin are generated. However, both of these substances are harmful to the human body and not only seriously pollute the environment, but also hydrochloric acid corrodes the incinerator. From this point of view, there is a movement to exclude vinyl chloride polymers from products that may enter municipal waste. Of course, vinyl chloride plastisols are also included therein.

Since plastisol itself is a product of very high utility value, naturally there is a great demand for a plastisol containing no chlorine, that is, a non-vinyl chloride plastisol. However, it is very difficult to synthesize polymer particles that give a plastisol having a performance comparable to that of vinyl chloride polymer, in particular, storage stability. Particles of simple polymers and copolymers are far from being practical, and various ideas have been elaborated.

As polymer particles for plastisols, acrylic polymers and styrene polymers have been proposed as alternatives to vinyl chloride polymers. Of course, simple acrylic polymers cannot meet the requirements for plastisol particles, so various conditions are applied. German Patent Nos. 2,454,235 and 2,529,732 propose acrylic polymer particles having a Tg of 35 ° C. or higher and defining a particle diameter and a particle composition determined in relation to the Tg. U.S. Pat. No. 4,071,653 proposes an acrylic polymer particle having a core / shell structure, which is composed of a core having excellent compatibility with a plasticizer and a shell having poor compatibility with the plasticizer. . In U.S. Pat. No. 4,176,028, plastisol particles in which acrylic polymer particles containing a carboxyl group or an amino group are neutralized with a volatile alkali or acid in a gas phase are proposed,
U.S. Pat. No. 4,613,639 proposes styrene copolymer plastisol particles with bound protective colloids. However, none of them has reached the range of vinyl chloride polymers in terms of storage stability.

[0006]

The problem to be solved by the present invention is that the plastisol having a polymer composition containing no chlorine directly provides a high level of storage stability which cannot be achieved by the conventional techniques. At the same time, it is also intended to improve the heat resistance of the plastisol film obtained by heating it.

[0007]

The present invention basically comprises
An unsaturated carboxylic acid compound and an ethylenically unsaturated compound are polymerized by, for example, emulsion polymerization in water to form a particulate polymer, and when it is in a water-dispersed state, the carboxyl group of the polymer particles is converted to an alkaline metal compound. The polymer particles obtained by neutralizing and then drying are used for plastisol. The plastisol produced by the particles thus obtained not only shows significantly better storage stability than the plastisol produced by the particles in which the same polymer is not neutralized with an alkaline metal compound, but also when it is heated. The heat resistance of the resulting plastisol film is significantly improved compared to that of plastisol film made from unneutralized polymer. The choice of the alkaline metal compound used for neutralization is important, as it determines all of the important plastisol performance, such as storage stability of the plastisol, film formation temperature and heat resistance of the film.

The ratio of the unsaturated carboxylic acid compound and the ethylenically unsaturated compound constituting the copolymer is 3 to 20 parts by weight, preferably ethylenic unsaturated carboxylic acid compound to 80 to 97 parts by weight of the ethylenically unsaturated compound. The unsaturated carboxylic acid compound is 4 to 12 parts by weight with respect to 88 to 96 parts by weight of the unsaturated compound. Here, the unsaturated carboxylic acid compound may be a single compound or a mixture of different compounds. The ethylenically unsaturated compound may be a single compound or a mixture of different compounds. When the relative amount of the unsaturated carboxylic acid is less than 3 parts by weight, the viscosity stability of the obtained plastisol becomes poor, while when the relative amount of the unsaturated carboxylic acid exceeds 20 parts by weight, film formation is not possible. It becomes defective.

Examples of the ethylenically unsaturated compound which can be used as a monomer constituting the plastisol copolymer particles of the present invention include styrene and its derivatives, methacrylic acid ester having an alkyl group having 1 to 8 carbon atoms or acrylic acid. Ester and fatty acid residues have 1 to 10 carbon atoms
8 vinyl ester, acrylonitrile and its derivatives, butadiene and its derivatives and the like. On the other hand, examples of the unsaturated carboxylic acid compound which is the other monomer constituting the copolymer include acrylic acid, methacrylic acid, maleic acid and its monoester, itaconic acid and its monoester, fumaric acid and its monoester, and the like. Can be mentioned.

Copolymer particles are produced by emulsion or suspension polymerization. Emulsion polymerization is from 0.2 to all monomers.
It can be carried out by heating water containing 2% of an emulsifier and 0.05 to 5% of a polymerization initiator with stirring to 50 to 95 ° C., and adding a monomer thereto. The amount of monomer added is suitably in the range of 25 to 60%. here,
Although various emulsifiers can be used, examples thereof include sodium stearate, sodium oleate, sodium dodecylate, sodium lauryl sulfate, sodium polyoxyethylene nonylphenyl ether sulfate, sodium dodecylbenzene sulfonate, and dibutylsulfosuccinic acid. soda,
Polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitan monolaurate, polyvinyl alcohol, hydroxyethyl cellulose, sodium polyacrylate, sodium salt of styrene-maleic acid copolymer, etc. Examples include one kind or a combination of two or more kinds selected from the above. Various types of polymerization initiators can be used, but examples thereof include water-soluble initiators such as ammonium persulfate, sodium persulfate, potassium persulfate, hydrogen peroxide, and t-butyl hydroperoxide. 1 or 2 selected from agents
A combination of two or more kinds, or one or more kinds selected from benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, azobisisobutyronitrile, azobisdimethylvaleronitrile and other oil-soluble initiators. Or a combination of a peroxide and a reducing agent such as sodium sulfite, ammonium sulfite, ferrous oxide, cuprous oxide, sorbic acid and sucrose.
A polymerization time of 3 to 8 hours is required to complete the polymerization.

The size of the copolymer particles obtained in a single emulsion polymerization is not very large. Such a size depends on the composition and method of emulsion polymerization, but is at most 0.05-0.
It is about 3 μm. Therefore, seed polymerization is required if larger particles are desired. In seed polymerization, the emulsifier is added to the dispersion liquid of the copolymer particles that have already been polymerized to the extent that new emulsifier micelles do not occur, the polymerization initiator is added, and then the monomer is added under the conditions described above. It can be carried out by polymerizing. According to this method, the particles can be enlarged almost as calculated. In order to enlarge the particles as calculated, it is desirable to repeat the seed polymerization as little as possible.

The suspension polymerization is carried out by adding 0.05 to 5% of the monomer in which the oil-soluble initiator described above is dissolved to 0.5 to 5% of the water-soluble polymer and / or inorganic fine particles or water With a hydrophilic polymer / surfactant mixture,
It can be carried out by vigorously stirring at a monomer concentration of 15 to 50% to emulsify it in water, and heating to 60 to 95 ° C. with gentle stirring. 4-8 to complete the polymerization
Need time. Examples of the water-soluble polymer used here include one or a combination of two or more selected from polyvinyl alcohol, hydroxyethyl cellulose, sodium polyacrylate, sodium salt of styrene-maleic acid copolymer and the like. Can be mentioned. Further, examples of the inorganic particles include one kind or a combination of two or more kinds selected from calcium phosphate, calcium carbonate, magnesium hydroxide, talc, clay and the like. Furthermore, examples of the surfactant include sodium stearate,
Sodium oleate, sodium dodecylate, sodium lauryl sulfate, sodium polyoxyethylene nonyl phenyl ether sulfate, sodium dodecylbenzene sulfonate, sodium dibutyl sulfosuccinate, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether,
1 selected from polyoxyethylene oleyl ether, polyoxyethylene sorbitan monolaurate, etc.
And a combination of two or more kinds.

The copolymer particles produced in this way are
Much larger than those produced by emulsion polymerization. The particle size obtained is from several μm to several tens of μm, depending on the composition of suspension polymerization and the stirring conditions. Unlike emulsion polymerization, seed polymerization cannot be applied, so post-particle size control is not possible.

In either method, the polymer particles produced are neutralized with the alkaline metal compound at a temperature of 5 ° C. to 95 ° C. and a pH of 7 to 14 in a dispersed state, and then dried. , A powder polymer as a plastisol resin.
For neutralization, it is preferable to use an aqueous solution of an alkaline metal compound, and a spray dryer is generally used for drying.

The number average particle size of particles (primary particles) produced by emulsion polymerization is preferably 0.1 μm or more,
0.3 μm or more is more preferable. If this value is less than 0.1 μm, the viscosity stability of plastisol is poor. Particles obtained by spray drying have a diameter of several μm to several hundred μm.
However, these are secondary particles obtained by aggregating and condensing a large number of primary particles, and when dispersed in a plasticizer, they are dispersed in the primary particles except for a part by a stirring action. Therefore, it is important for the primary particles to control important plastisol performances such as the amount of plasticizer required for plastisolization, fluidity and storage stability of plastisol, and film formation rate (that is, absorption rate of plasticizer). It is the size. The larger the primary particles, the less the plasticizer required for plastisol formation, and the better the storage stability of plastisol, but the slower the absorption rate of the plasticizer, the longer the heating time required for film formation. become. Therefore, there should be a suitable region where the two extremes are eclectic. However, according to the research by the present inventor, the number average particle size is 0.1 in this region.
μm or more and 100 μm or less, preferably 0.3 μm or more 2
It is considered to be 0 μm or less.

The desired plastisol storage stability and high heat resistance of plastisol film cannot be obtained only by introducing a carboxyl group into the polymer by copolymerization of an ethylenically unsaturated compound and an unsaturated carboxylic acid compound. It is only after neutralizing the carboxyl group of the polymer with an alkaline metal compound that the storage stability of the plastisol and the heat resistance of the plastisol film can be achieved. Examples of alkaline metal compounds that can be used for this purpose include monovalent alkaline metal compounds sodium hydroxide, potassium hydroxide, and divalent alkaline metal compounds calcium hydroxide, barium hydroxide, magnesium acetate, acetic acid. Examples thereof include zirconyl, zinc ammonium chloride, zinc ammonium acetate, zirconyl ammonium acetate, aluminum hydroxide which is a trivalent alkaline metal compound, and basic aluminum acetate. Alkali metals that are divalent rather than monovalent and trivalent rather than divalent give excellent stability and high heat resistance temperatures, but at the same time, the film forming temperature rises. Therefore, the type of alkaline metal to be used must be selected so that it is most suitable for the purpose of plastisol.

The degree of neutralization of the carboxyl groups also has a great influence on the important plastisol performance. The higher the degree of neutralization, the higher the storage stability and the heat resistance of the film, but at the same time, the higher the temperature at which the film is formed. In actual neutralization, it is impossible to completely neutralize the carboxyl groups of the polymer. The degree of neutralization varies considerably depending on the type of unsaturated carboxylic acid compound and the particle size. For example, if the number average particle size of the styrene polymer is 7% by weight of methacrylic acid and the number average particle size is about 0.5 μm, it is 18%. Average particle size is about 0.7
It is about 73% in μm. This is probably because the alkali metal compounds neutralize only the carboxyl groups on the surface or the layer near the surface, and the ions do not penetrate deep inside the particles to neutralize the carboxyl groups. . In addition, the degree of neutralization is significantly higher in the copolymer particles obtained by copolymerizing more hydrophilic acrylic acid than in the methacrylic acid copolymer particles, but the latter shows that more carboxyl groups are distributed on the particle surface and in the vicinity thereof. It is thought that it is because it is done. Practically, the degree of neutralization does not necessarily have to be 100%,
In the plastisols of the present invention, at least 10% of the polymer carboxyl groups must be neutralized. When the degree of neutralization is 10% or less, plastisol storage stability and heat resistance of the plastisol film that can be practically used cannot be obtained. In practice, it is preferred to have a degree of neutralization of 10-80%.

It is desirable that the secondary particles produced by spray-drying should be as easily dispersed as possible in the primary particles during plastisol preparation. This is because the secondary particles are porous and absorb the plasticizer which is not related to fluidization, so that the amount of the plasticizer used increases. As the amount of plasticizer used increases, the plastisol film becomes more flexible and loses its adaptability for applications requiring a tough film. In order to form secondary particles that easily break into primary particles, it is desirable that the spray drying temperature is as low as possible and the Tg of the polymer is as high as possible. However, even if the spray drying temperature is lowered, there is an upper limit of drying efficiency,
Even if it is lowered at most, it is 50 ° C. Therefore, the Tg of the polymer is naturally limited, and it is desirable to set the temperature to 50 ° C. at the lowest, as described above.

The plastisol copolymer particles thus obtained are dispersed in a plasticizer to form a plastisol.
Examples of plasticizers that can be used here include phthalates such as dioctyl phthalate, dibutyl phthalate, diisobutyl phthalate, butyl cyclohexyl phthalate, butyl octyl phthalate, dicapryl phthalate, and diisodecyl phthalate, di-2-ethylhexyl adipate, diisodecyl adipate. Adipic acid ester, tricresyl phosphate, phosphoric acid ester such as 2-ethylhexyl phosphate, dioctyl azelate, tri-2-ethylhexyl citrate,
Mention may be made of citric acid esters such as acetyltributyl citrate, acetylated glycerides such as glycerol diacetate laurate, epoxidized glycerides such as epoxidized soybean oil and epoxidized linseed oil.

The plasticizer affects the fluidity, film forming property and film physical properties of the plastisol. Basically, compatibility with polymers is important. If the compatibility is extremely inferior, it does not melt to form a continuous film even if heated, but even if slightly inferior, the plasticizer exudes from the inside to the film surface after the film is formed, which is a practical problem. Therefore, it is important to carefully select the plasticizer for compatibility with the polymer and carefully select it. The addition amount is 50 to 2 with respect to 100 parts by weight of the polymer particles for plastisol.
It is in the range of 00 parts by weight.

The fluidity of the plastisol and the physical properties of the film can be adjusted by various additives. If necessary, the above various properties are adjusted by adding additives such as a surfactant, a pigment, a filler, a foaming agent and a solvent. Of these, the solvent is functionally the same as the plasticizer, but since it volatilizes after the film is formed, the fluidity of the plastisol can be improved without softening the formed film. However, the addition of a too large amount of solvent impairs the characteristics of plastisol, so the addition amount of the solvent should be kept within 10 parts by weight with respect to 100 parts by weight of plastisol polymer.

The present invention will be described in more detail below with reference to comparative examples and examples.

Comparative Example 1 Internal volume 1,000 equipped with a stirrer and a reflux condenser
To a glass polymerization apparatus of ml, 200 g of styrene (hereinafter referred to as "St") and 592 g of pure water were charged, and 50 g of sodium alkyldiphenyl ether disulfonate (manufactured by Kao Corporation, trade name Perex SS-L) was used as an emulsifier. % Aqueous solution 4 g and ammonium persulfate 10% aqueous solution 4 g were added, and the temperature was raised to 90 ° C. while stirring at 250 rpm. After heating for 4 hours, no reflux of styrene was observed. Further, the reaction was continued for 2 hours under the same conditions to complete the polymerization. The solid content of the polystyrene latex thus obtained was 24.5% (polymerization rate: 98%). The number average particle diameter is 0.05 μm when measured with an electrophoretic light scattering photometer ELS-800 type manufactured by Otsuka Electronics Co., Ltd.
Met.

A spray dryer (manufactured by Yamato Scientific Co., Ltd., having a solid content concentration of 12.5% and a nozzle aperture of 711 μm,
PALVIS mini GS35 type) with an inlet temperature of 120
C., and outlet temperature 60.degree. C. for spray drying. The particles obtained are
The particles were porous secondary particles having a diameter of 5 μm to 200 μm.

The polymer powder for plastisol thus obtained was dispersed in dioctyl phthalate (hereinafter referred to as "DOP") to form a plastisol. No particle dispersion was obtained.

Comparative Examples 2 to 4 Monomers were changed from St alone to a mixed monomer of St / methacrylic acid (hereinafter referred to as “MAA”) (93/7), and other conditions were completely the same as those of Comparative Example 1. In the same way,
A St / MAA (93/7) copolymer latex was synthesized. The polymerization rate was 98%, and the number average particle diameter was 0.06 μm.

The latex thus obtained was divided into three parts. In Comparative Example 2, one of them was used as it was, in Comparative Example 3, the other was neutralized with sodium hydroxide, and in Comparative Example 4, the remaining one was neutralized with calcium hydroxide. Neutralization was performed by adding a 5% aqueous solution of sodium hydroxide to adjust the pH to 9.5. The amount of sodium hydroxide added here corresponded to the amount which neutralized 28% of the copolymerized MAA. For calcium hydroxide, the saturated aqueous solution was added in an amount equal to that of sodium hydroxide for neutralization. Finally, the concentration was adjusted to 12.5% and spray-dried under the same conditions as in Comparative Example 1 to obtain plastisol polymer particles.

The plastisol polymer particles thus obtained were dispersed in DOP to obtain plastisol. Amount of DOP added to make plastisol, its initial viscosity, 23
Table 1 and Table 2 collectively show the storage stability (viscosity increase rate) at 0 ° C, the minimum film forming temperature, the heat resistant temperature, and the transparency of the film. The storage stability, the minimum film forming temperature and the heat resistant temperature were measured by the following methods.

Storage stability The viscosity of plastisol was measured at room temperature (23 ° C) using a B-type viscometer manufactured by Tokyo Keiki Co., Ltd. Since plastisol exhibits thixotropic properties, the viscosity was taken as the value when equilibrium was reached. The storage stability was represented by the ratio of the viscosity measured after standing at room temperature divided by the viscosity immediately after the preparation of plastisol (initial viscosity).

Minimum film forming temperature Several samples were prepared by coating plastisol on aluminum foil to a thickness of about 1 mm. This sample was heated at a predetermined temperature for 10 minutes and then cooled, and it was sensoryly judged whether or not a continuous film was formed. The test was started from 80 ° C., and the heating temperature was increased in steps of 10 ° C. to determine the minimum temperature at which a continuous film was formed.

Heat resistant temperature Plastisol is heated at 180 ° C. for 20 minutes to give a thickness of about 4 m.
m plastisol sheet was prepared. Using this sheet as a sample, the heat resistant temperature was measured using TMA (120C type manufactured by Seiko Denshi Kogyo). The probe used is 2m in diameter
m needle probe, weight 10 g.

Cool the sample sheet to -5 ° C. and set it,
The temperature was raised at a rate of 4 ° C / min. Penetration was started waiting for the temperature to rise to 0 ° C. and penetration was measured as a function of temperature. Penetration will remain zero at the beginning of temperature rise,
Or just slower speed,
When the temperature peculiar to the sample sheet was exceeded, the speed rapidly increased and hit the quartz glass stand and stopped. The heat resistant temperature was a temperature at which the probe penetrated 50% of the thickness of the measurement sample sheet.

Comparative Example 5 Using the unneutralized latex of Comparative Example 2 as a seed, the particle size was enlarged by a seed polymerization method which is usually performed. The surface tension of the unneutralized latex of Comparative Example 2 used as a seed is 65 dyne / cm.
Therefore, first, a 10% aqueous solution of sodium alkyldiphenyl ether disulfonate was added to adjust the surface tension to a value equal to or less than the critical micelle concentration of this surfactant.
Stabilized by lowering to 0 dyne / cm and adjusting the concentration to 20%. To 5 g of this stabilized seed latex, pure water 592
g, 200 g of St / MAA (93/7) mixed monomer,
Add 4 g of a 10% aqueous solution of ammonium persulfate to 250
The temperature was raised to 90 ° C. with stirring at rpm. After heating for 4 hours, no reflux of styrene was observed. Further, the reaction was continued for 2 hours under the same conditions to complete the polymerization. The polymerization rate was 98%, and the number average particle diameter was 0.23 μm.
Using this as seed latex, the St / MAA (9
3/7) The seed particles were polymerized with a mixed monomer to enlarge the latex particles. The polymerization rate was 98%, and the number average particle size was 0.53 μm.

Plastisol polymer particles were prepared by the method described in Comparative Example 2, and then DOP was blended to obtain plastisol. Performances related to plastisol are shown in Table 1 and Table 2.
Shown in.

Comparative Example 6 and 7 In accordance with the first stage seed polymerization method of Comparative Example 5, except that a mixed monomer of St / MAA (97.8 / 2.2) was used as St. / MAA (97.8 / 2.2) copolymer latex was synthesized. The polymerization rate was 98%, and the number average particle diameter was 0.26 μm. Comparative Example 6 was neutralized with sodium hydroxide in the same manner as in Comparative Example 3, and Comparative Example 7 was neutralized with calcium hydroxide in the same manner as in Comparative Example 4 and spray-dried to obtain plastisol polymer particles. Next, it was made into plastisol by DOP. The properties related to plastisol are shown in Tables 1 and 2.

Examples 1 and 2 For the latexes obtained in Comparative Example 5, sodium hydroxide was used in Example 1 as in Comparative Example 3 and water was used in Example 2 as in Comparative Example 4. Each was neutralized with calcium oxide and then spray-dried to obtain plastisol polymer particles. Various properties were measured by DOP as plastisol. The results are shown in Tables 1 and 2.

Example 3 The plastisol polymer particles of Example 1 were replaced with glycerol diacetate monolaurate (hereinafter "G") in place of DOP.
(Hereinafter referred to as "DML") was blended to obtain a plastisol. The properties relating to plastisol are shown in Tables 1 and 2.

Examples 4 and 5 Plastisols were prepared by blending the plastisol polymer particles of Examples 1 and 2 with diisononyl diphthalate (hereinafter referred to as "DINP") instead of DOP. The properties related to plastisol are shown in Tables 1 and 2.

In accordance with the two-step seed polymerization method of Comparative Example 5, except that a mixed monomer of St / MAA (96/4) was used as the monomer in Examples 6 and 7 .
A St / MAA (96/4) copolymer latex was synthesized. The obtained latex was neutralized with sodium hydroxide in Example 6 as in Comparative Example 3 and calcium hydroxide in Example 7 as in Comparative Example 4 and then spray-dried. To obtain plastisol polymer particles. Next, various properties were measured as plastisol by DOP. The results are shown in Tables 1 and 2.

In accordance with the two-stage seed polymerization method of Comparative Example 5, except that a mixed monomer of St / MAA (91/9) was used as the monomers of Examples 8 and 9 .
St / MAA (91/9) copolymer latex was synthesized. The obtained latex was neutralized with sodium hydroxide in Example 8 as in Comparative Example 3 and calcium hydroxide in Example 9 as in Comparative Example 4, and then sprayed. Dried to obtain plastisol polymer particles. Next, various properties were measured as plastisol by DOP. The results are shown in Tables 1 and 2.

St / MAA (88/12) was obtained according to the two-step seed polymerization method of Comparative Example 5 except that a mixed monomer of St / MAA (88/12) was used as the monomers of Examples 10 and 11. A copolymer latex was synthesized. The obtained latex was neutralized with sodium hydroxide in Example 10 as in Comparative Example 3 and calcium hydroxide in Example 11 as in Comparative Example 4, and then sprayed. Dried to obtain plastisol polymer particles. Next, various properties were measured as plastisol by DOP. The results are shown in Tables 1 and 2.

Monomers of Examples 12 and 13 According to the two-stage seed polymerization method of Comparative Example 5, except that a mixed monomer of St / MAA (85/15) was used.
St / MAA (85/15) copolymer latex was synthesized. The obtained latex was neutralized with sodium hydroxide in Example 12 as in Comparative Example 3 and calcium hydroxide in Example 13 as in Comparative Example 4, and then spray-dried. To obtain plastisol polymer particles. Next, various properties were measured as plastisol by DOP. The results are shown in Tables 1 and 2.

Examples 14 and 15 St / acrylic acid (hereinafter referred to as "AA") as a monomer
Other than using the mixed monomer of (94.5 / 5.5),
According to the two-step seed polymerization method of Comparative Example 5, St / AA (9
4.5 / 5.5) A copolymer latex was synthesized. With respect to the obtained latex, sodium hydroxide was used in the same manner as in Comparative Example 3 in Example 14, and Example 15 was used.
In the same manner as in Comparative Example 4, with calcium hydroxide,
Each was neutralized and then spray dried to give plastisol polymer particles. Then as plastisol with DOP,
Its properties were measured. The results are shown in Tables 1 and 2.

In accordance with the two-stage seed polymerization method of Comparative Example 5, except that a mixed monomer of St / AA (92/8) was used as the monomer in Examples 16 and 17 ,
A t / MAA (92/8) copolymer latex was synthesized. The obtained latex was neutralized with sodium hydroxide in Example 16 as in Comparative Example 3 and calcium hydroxide in Example 17 as in Comparative Example 4 and then spray-dried. To obtain plastisol polymer particles. Next, various properties were measured as plastisol by DOP. The results are shown in Tables 1 and 2.

Examples 18 and 19 : In addition to using a mixed monomer of St / butyl acrylate (hereinafter referred to as "BA") / MAA (88/5/7) as the monomer, the two-stage batch seed of Comparative Example 5 was used. According to the law, S
A t / BA / MAA (88/5/7) copolymer latex was synthesized. About the obtained latex, Example 18
In the same manner as in Comparative Example 3, sodium hydroxide was used,
Further, in Example 19, similarly to Comparative Example 4, each was neutralized with calcium hydroxide and then spray-dried to obtain plastisol polymer particles. Next, various properties were measured as plastisol by DOP. The results are shown in Tables 1 and 2.

Examples 20 and 21 According to the two-stage seed polymerization method of Comparative Example 5, except that a mixed monomer of methyl methacrylate (hereinafter referred to as "MMA") / MAA (93/7) was used as the monomer. , MMA /
MAA (93/7) copolymer latex was synthesized. With respect to the obtained latex, sodium hydroxide was used in the same manner as in Comparative Example 3 in Example 20, and Example 2 was used.
In No. 1, as in Comparative Example 4, each was neutralized with calcium hydroxide and then spray-dried to obtain plastisol polymer particles. Then, various properties of plastisol were measured with acetyltributyl citrate (hereinafter referred to as "ATBC"). The results are shown in Tables 1 and 2.

Examples 22 and 23 The latexes obtained in Comparative Example 5 were neutralized with sodium hydroxide and spray-dried in the same manner as in Comparative Example 3 to obtain plastisol polymer particles. In Example 22, epoxidized soybean oil (hereinafter referred to as “ESB”) (Adeka Sizer O-130P, manufactured by Asahi Denka Co., Ltd.)
In Example 23, epoxidized linseed oil (hereinafter,
"ELS") (manufactured by Asahi Denka Kogyo Co., Ltd., ADEKA CIZER O-180A) was used as plastisol, and its properties were measured. The results are shown in Tables 1 and 2.

[0048]

[Table 1]

[Table 2] As is apparent from the above Comparative Examples and Examples, the storage stability, which is the most important property in practice for plastisols, depends on the type of unsaturated carboxylic acid compound and the copolymerization rate, the type of neutralizing alkali metal, and the primary It is governed by particle size.
For unsaturated carboxylic acid compounds, the higher the copolymerization rate in the copolymer, the better the storage stability.
Further, even if the copolymerization rate is the same, a type more likely to be distributed on the particle surface, that is, a type having a higher neutralization rate with an alkaline metal gives higher storage stability. Even if a carboxyl group is introduced into the polymer using an unsaturated carboxylic acid compound as a comonomer for copolymerization, high storage stability cannot be expected if the carboxyl group remains unneutralized, but the carboxyl group is neutralized with an alkali metal compound. By doing so, the storage stability of the plastisol is significantly increased. Regarding the improvement of stability, the higher the valence of the alkali metal used for neutralization, the more effective it is. As for the particle size, the larger the particle size, the better the storage stability, but the number average particle size is less than 0.
If it exceeds 3 μm, the improvement effect is not so remarkable.

Among the measures for improving the storage stability, selection of unsaturated carboxylic acid compounds that are easily distributed on the particle surface,
Neutralization of a carboxyl group with a high copolymerization rate of an unsaturated carboxylic acid compound and a high valent alkaline metal compound is
It also aims to increase the heat resistance of the plastisol film.
However, this direction also impairs the plastisol film formability. If the minimum film forming temperature also exceeds 250 ° C. by heating for 5 minutes, there will be a problem in practical use. Therefore, in order to balance the storage stability, the film forming property, and the heat resistance of the film, which are important as plastisol performance, an appropriate compromise is required.

In the present invention, the copolymerization rate of the unsaturated carboxylic acid compound is 80 to 80% of the ethylenically unsaturated compound.
3 to 20 parts by weight of unsaturated carboxylic acid compound based on 97 parts by weight
Parts by weight, preferably 88-96 ethylenically unsaturated compounds
The unsaturated carboxylic acid compound is 4 to 12 parts by weight with respect to parts by weight, and the size of the primary particles is such that the number average particle diameter is 0.1 μm or more and 100 μm or less, preferably 0.3 μm.
It is 20 μm or less. Such a copolymer is made into a water-dispersed liquid state, the carboxyl group is neutralized with an alkali metal compound that gives the required heat-resistant temperature, and then spray-dried to form plastisol polymer particles, and a plasticizer and, if necessary, an additive are added. In addition, plastisol ensures long-term storage stability at room temperature.

[0051]

As described above, according to the present invention,
The chlorine-free polymer composition enables a plastisol having a high level of storage stability and a plastisol film having a high heat resistant temperature and excellent weather resistance, which cannot be achieved by the conventional technique. This plastisol replaces it in applications such as transportation vehicles, ships, toys, and processed textile products where vinyl chloride plastisols have been used in the past.
Not only will it contribute to environmental pollution, but it will also be able to exploit new uses that could not be achieved with vinyl chloride-based plastisols by utilizing its high heat resistance temperature and excellent weather resistance.

Claims (2)

[Claims] 1. A copolymer of 3 to 20 parts by weight of an unsaturated carboxylic acid compound and 80 to 97 parts by weight of an ethylenically unsaturated compound, wherein at least 10% of its carboxyl groups are neutralized with an alkaline metal compound. 100 parts by weight of polymer particles having a number average particle diameter of 0.1 μm or more and 100 μm or less are dispersed in 50 to 200 parts by weight of a plasticizer. 2. An unsaturated carboxylic acid compound in an amount of 3 to 20 parts by weight and an ethylenically unsaturated compound in an amount of 80 to 97 parts by weight are polymerized in water, and at least 10% of the carboxyl groups of the polymer obtained are alkaline metal compounds. The method for producing the plastisol according to claim 1, wherein